How to sequence actuators to perform two or more tasks in sequence
You need to sense the end of the previous operation to start the next one. 

As motion actuators (mentioned in your screen shoot) have no end you can start the followup operation when you deactivate the current one.

According to your description I suggest to use steering actuators with enabled self-termination together with the method described in How to start second action after check that first one is done in bge?.

This allows you to let the enemies patrol between various checkpoints. Moving to a specific checkpoint is represented/performed by a single steering actuator.

I hope it helps.